A method of making 3D integrated circuits and a 3D integrated circuit structure. There is a first semiconductor structure joined to a second semiconductor structure. Each semiconductor structure includes a semiconductor wafer, a front end of the line (FEOL) wiring on the semiconductor wafer, a back end of the line (BEOL) wiring on the FEOL wiring, an insulator layer on the BEOL wiring and a metallic layer on the insulator layer. The first semiconductor structure is aligned with the second semiconductor structure such that the metallic layers of each of the semiconductor structures face each other. The metallic layers of each of the semiconductor structures are in contact with and bonded to each other by a metal to metal bond wherein the bonded metallic layers form an electrically isolated layer.